Organic Light Emitting Display (OLED) has self-luminous, low driving voltage, high luminous efficiency, short response time, sharpness and contrast, nearly 180° viewing angle, wide temperature range, flexible, large-area panchromatic and many other advantages, which is recognized as the most promising display device in the field.
OLED can be classified into passive matrix OLED (PMOLED) and active matrix OLED (AMOLED) according to the driving mode, that is, direct addressing and thin film transistor (TFT) matrix addressing. Among them, AMOLED has a matrix arrangement of pixels, belonging to the active display type with high luminous efficiency, is usually used for high-definition large-size display device.
OLED display technology is different from the traditional liquid crystal display technology, it does no need backlight, and adopts a very thin layer of organic materials and glass substrates. When the current goes through, these organic materials will light. However, due to organic materials easily react with water vapor or oxygen, these organic materials applied in display device is very demanding on encapsulation of OLED display. Therefore, it is crucial for a stable luminescence of OLED devices by improving the encapsulation inside the OLED device and isolating the OLED device from the external environment as far as possible.
At present, the encapsulation of a large-sized OLED device is mainly achieved by coating a sealant (dam) on a hard-cover plate (such as glass or metal), placing a moisture absorbent (getter) inside the sealant, then matching the encapsulation cover plate coated with the sealant to the TFT substrate provided with the OLED device, and curing the sealant to complete the encapsulation. However, since the sealant is generally made of an organic substance, the structure of which cannot be tightly sealed even when the sealant is cured, the effect of blocking the water and oxygen is not good either. At the same time, although the moisture absorbent can absorb water vapor, it merely delays water vapor intruding into the OLED device, and does not fundamentally prevent the intrusion of water and oxygen, so that the encapsulation structure of the water-oxygen barrier performance is poor.
As a new material developed in recent years, alloys of indium and indium have some unique properties that have low permeability to moisture and oxygen, low melting point, good plasticity, a certain degree of flexibility, and a wide application prospect in the electronics industry. Among them, a binary eutectic alloy composed of indium and gallium has a similar density to the solid metal, excellent water-oxygen barrier performance, and flowable at room temperature. When exposed to air, oxygen in the air reacts with the binary eutectic alloy composed of indium and gallium at room temperature, and gradually hardening on the surface of the material to form an very dense oxide with excellent water-oxygen barrier property. Meanwhile also preventing the interior of the material from being oxidized so that the interior remains liquid and thus remains flexible.